This invention relates to spindles for supporting and rotating one or more memory disks in a disk drive.
In a typical spindle, the disks are clamped to a cylindrical hub, which in turn is mounted to a shaft. A motor mounted within the hub rotates the hub and disks. In some spindles, the shaft and hub are axially mounted on and rotate together about a stationary tube secured to the base of the disk drive; in others, the shaft is the stationary member. A bearing assembly (e.g., that includes individual ball bearings or hydrodynamic bearings) permits the relative rotation between the rotatable and stationary members of the spindle. In both types of spindles, the stator of the motor is secured to the stationary member (i.e., the support tube or the shaft), and the rotor is mounted within a cavity in the lower end of the hub.
Some spindles use cartridge bearing assemblies, that is, bearing assemblies in which the outer races of the individual bearings are formed (such as by machining) in a single sleeve. In others, the outer races of the individual bearings are formed in separate rings that are axially separated by a spacer.